1. Field of the Invention
The present invention relates to a film-reinforced glass which has excellent impact resistance and penetration resistance (resistance to passing through) and is effective in prevention of crimes, and which is used for an automobile, a railway vehicle, a building and a showcase, and a process for the preparation thereof. The invention relates to an adhesive film that can be advantageously utilized for the preparation of the film-reinforced glass. Furthermore, the invention relates to a side window of an automobile comprising the film-reinforced glass.
2. Description of the Related Art
As a glass used in automobile, especially windshield, a laminated glass having a structure that two sheets of glass are bonded through a transparent adhesive layer (intermediate layer) is generally employed. The transparent adhesive layer is, for example, composed of PVB (polyvinyl butyral) layer, and the use of the transparent adhesive layer enhances penetration resistance of the laminated glass. If external impact is given to the laminated glass, the transparent adhesive layer prevents the glass broken by the impact from scattering because the layer adheres to pieces of the broken glass. Even if the laminated glass for automobile is destroyed for the purpose of robbery or invasion, the window of the laminated glass cannot be opened. Hence, the laminated glass is useful as glass for prevention of crimes.
In contrast, a side window (side glass) of automobile such as a door glass and a glass inserted in window is scarcely destroyed due to traffic accident, and therefore the glasses do not need the penetration resistance that the above-mentioned laminated glass has. As a result, for the door glass, a sheet of glass comprising slightly reinforcing glass has been employed. However, in case only such a sheet of glass is used in the door glass, the use brings about the following disadvantages:
(1) the glass is poor in impact resistance and penetration resistance (passing through resistance) compared with the laminated glass;
(2) when the glass is destroyed for the purpose of robbery or invasion, it turns into many pieces of the glass to permit window to open.
Therefore, it is also now under investigation to use a glass having characteristics of the laminated glass for the side window of an automobile (e.g. a door glass and inserted glass).
As the laminated glass, especially the door glass of automobile, JP-A61-155232 describes a safety glass in which a plastic film is superposed on a glass plate through an intermediate film of ethylene-vinyl acetate copolymer (EVA) and further a cured layer is formed on the plastic film.